JPH09222747A - Image forming method and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely separate a transfer material from a photoreceptor by allowing a specific separation auxiliary to exist between the photoreceptor and the transfer material, so as to separate them. SOLUTION: An electrostatic latent image on the photoreceptor 1 is transferred from the photoreceptor 1 to the transfer material 4 by a transfer electrode 7. In a transfer material separating part, 8, the transfer material 4 and the photoreceptor 1 are separated. A separation process is the one of separating the photoreceptor 1 and the transfer material 4, in such a manner that the moving speed of the surface of the photoreceptor 1 is made >=250mm/sec, the radius of curvature of the photoreceptor 1 is made 30-200mm and a separation auxiliary whose particle size is 10-50μm and L* is 80-100 in color space shown by L* a* b* exists between the photoreceptor 1 and the transfer material 4. The separation auxiliary is supplied to the photoreceptor 1 from a developer incorporating the separation auxiliary. As this auxiliary, various kinds of inorganic particles and resin particles and further, a blended particle having the inorganic particle on the surface of the resin particle are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method capable of reliably separating a transfer material and an electrostatic charge image developer capable of improving the separation performance of the transfer material.

[0002]

2. Description of the Related Art At present, as a method for forming a visible image from certain image information, a method via an electrostatic latent image such as an electrophotographic method, an electrostatic recording method and an electrostatic printing method is widely known. There is. For example, in electrophotography, a uniform electrostatic charge is applied to a latent image carrier (hereinafter also referred to as a photoconductor) having a photosensitive layer made of a photoconductive material, and then the latent image carrier is exposed by exposing the document. An electrostatic latent image corresponding to the original is formed on the surface of the body, and the electrostatic latent image is developed by a developer to form an image of colored particles. After the toner image is transferred to a transfer material such as paper, the transfer material is separated from the latent image carrier and fixed by heating or pressing to form a copy image. On the other hand, the latent image carrier after the transfer step is cleaned of residual toner remaining on the latent image carrier without being transferred, and is then used for forming a next copy image.

Various methods are known as methods for separating the transfer material from the latent image carrier as described above. When roughly classified, a separating means such as a separating claw or a separating belt is brought into contact with the recording body. Method to forcibly separate the transfer material, air blowing method to the boundary between the transfer material tip and the latent image carrier, suction method from the back surface of the transfer paper, or corona discharge method to eliminate the charge on the back surface of the transfer material There is a method of separating the transfer material without contacting the separation means with the latent image carrier.

The latter separation method has the advantage that it does not damage the latent image carrier, but the separation of the transfer material is carried out by electrostatically attracting the transfer material electrostatically adsorbed on the latent image carrier. Because it is done by giving the power to overcome,
Separation performance from the photoconductor is not perfect.In reality, due to environmental fluctuations, variations in paper strain, instability of discharge, etc. When the effect cannot be expected, paper jams in the separation part cannot be avoided, and improvement of the reliability of separation has been a conventional problem. Further, in recent years, with the use of recycled paper for environmental protection, the diversification of transfer paper typified by an increase in double-sided copying, and the increase in copying speed, further improvement in separation performance is desired.

[0005]

In view of the above circumstances, an object of the present invention is to provide an image forming method with improved separation performance,
And to provide a developer.

[0006]

The above object of the present invention is achieved by the following constitution.

(1) A developing step of developing an electrostatic latent image on a moving photoreceptor, a transferring step of transferring a toner image visualized by the development onto a transfer material, and a transferring step of carrying the toner image. In the image forming method having a separation step of separating the material, in the separation step, the moving speed of the photoconductor surface is 250 mm.
/ Sec or more, the radius of curvature of the photoconductor is 30 to 200 mm
And the particle size is 10 to 50 μm,

[0008]

[Outside 5]

An image forming method, characterized in that it is a separation step in which the separation auxiliary agent is present between the photoconductor and the transfer material for separation.

(2) The image forming method described in (1) above, wherein the separation step is an electrostatic separation step.

(3) The image formation according to 1 or 2 above, wherein the separation aid is present between the photoconductor and the paper by supplying the separation aid from a developer containing the separation aid to the photoconductor. Method.

(4) The particle size is 10 to 50 μm,

[0013]

[Outside 6]

A developer containing a separation aid and a toner.

(5) A developing step of developing an electrostatic latent image on a moving photosensitive member, a transferring step of transferring a toner image visualized by the developing onto a transfer material, and a transferring step of carrying the toner image. In the image forming method having a separation step of separating the material, in the separation step, the moving speed of the photoconductor surface is 250 mm.
/ Sec or more, the radius of curvature of the photoconductor is 30 to 200 mm
And the particle size (μm) is 1.10 to 10 times the toner particle size (μm),

[0016]

[Outside 7]

An image forming method, characterized in that it is a separation step in which the separation auxiliary agent is present between the photoconductor and the transfer material for separation.

(6) The image forming method according to the above item 5, wherein the separation step is an electrostatic separation step.

(7) The separation aid described in 5 above is present between the photoconductor and the paper by supplying the separation aid from a developer containing the separation aid to the photoconductor. Image forming method.

(8) The particle size (μm) is the toner particle size (μ
1.10 times or more and 10 times or less of m),

[0021]

[Outside 8]

A developer containing a separation aid and a toner.

The present invention will be described in more detail. The separation aid of the present invention reduces the electrostatic attraction force between the photoconductor and the transfer material by maintaining an appropriate distance between the photoconductor and the transfer material during the separation step, and thus the movement of the photoconductor is prevented. Speed is 250mm /
sec or more, the radius of curvature of the photoconductor at the time of separation is 30 to
The separability can be improved even under the condition of 200 mm, which is very severe for separation.

The particle size dp of the separation aid of the present invention is 10-5.
0 μm,

[0025]

[Outside 9]

With this, the separation performance can be improved even when the moving speed and the radius of curvature of the photoconductor are as described above.

If the particle size of the separation aid is too small, the distance between the photoconductor and the transfer material cannot be maintained properly, so that good separation performance cannot be obtained. If the particle size of the separation aid is too large, the photoconductor may be damaged. A more preferable range of the particle size of the separation aid is 13 to 30 μm.

Further, between the particle size dp of the separation aid and the particle size dt of the toner, 1.10 dt ≦ dp ≦ 10 dt (μm)
Have a relationship

[0029]

[Outside 10]

If the moving speed and the radius of curvature of the photosensitive member are as described above, the separation performance can be improved.

If the particle size of the separation aid is too small as compared with the particle size of the toner, the distance between the photoconductor and the transfer material cannot be maintained properly, and good separation performance cannot be obtained. If the particle size of the separation aid is too large as compared with the particle size of the toner, the photoconductor may be damaged or transfer failure may occur. A more preferable range of the ratio of the average particle diameter dt of the toner and the average particle diameter dp of the separation aid is 1.30dt ≦ dp.
≦ 3 dt (μm).

The average particle size of the toner and the separation aid means the average particle size on a volume basis, and is a laser diffraction type particle size distribution measuring device "HELOS" equipped with a wet disperser (SYMPATEC company). Manufactured).

In order not to disturb the copied image, it is desirable that the separation aid does not transfer to the transfer material, but in reality, there are some separation aids that are transferred. Therefore, the separation aid is preferably a material having a small coloring power, and in the present invention,

[0034]

[Outside 11]

It is necessary that, and more preferably

[0036]

[Outside 12]

Is as follows. Chromaticity is as follows: optical path length 1 cm, depth 4.
Put the sample in a 5 cm cell and tap it well,
Macbeth Color Eye 7000 (Division of
Koomorgen Instrument Cor
poration) and the like.

When the moving speed of the photosensitive member is less than 250 mm / sec, the effects of the present invention are not exhibited because the photosensitive members are relatively easily separated. The upper limit of the moving speed of the photoconductor is restricted from a practical viewpoint as a machine.

When the radius of curvature of the photoconductor is smaller than 30 mm, the photoconductor can be separated from the photoconductor by the rigidity of the transfer material, so that the effect of the separation aid is not exhibited. When the radius of curvature is large, the separation effect due to the rigidity of the transfer material cannot be expected, so that the effect of the separation aid is exhibited. The maximum value of the radius of curvature is restricted from a practical point of view for making the machine a certain size.

The separation step of the present invention will be described. When the photoconductor 1 has a drum shape, as shown in FIG. 1, the electrostatic latent image on the photoconductor is transferred from the photoconductor to the transfer material 4 by the transfer electrode 7, and is separated by the transfer material separating unit 8 at the separation electrode. The transfer material and the photoconductor are separated by 6, and the transfer material is discharged by the transport mechanism 5. The residual toner is scraped off by a cleaning blade and collected. In this case, the radius of curvature of the present invention is equal to the radius (a) of the photoconductor.

When the photoconductor is in the form of a belt, as shown in FIG. 2, the original 1 placed on the contact glass 12
0 is exposed by the flash lamps 11 and 11 ',
An electrostatic latent image is formed on the belt-shaped photoreceptor 13. The belt-shaped photoreceptor 13 includes a driving roller 14 and driven rollers 15, 15 '.
Is moved in the direction of the arrow, and the generated electrostatic latent image is
After the image is transferred by the transfer separation charger 18 after being developed by the developing device 17 and brought into close contact with the transfer material 4, the transfer material 4 is transferred.
Is separated from the photoconductor. The toner remaining on the photoconductor is removed by the cleaning device 19. Static elimination lamps 16, 1
6'removes electrostatic charges on the photoconductor. Driven roller 1 of FIG.
5 is enlarged and shown in FIG. In FIG. 3, the belt-shaped photoconductor 13 moves in the direction of the arrow, but the transfer separation charger 18 is composed of the transfer electrode 7 and the separation electrode 6, and the transfer material 4 is separated from the photoconductor by the transfer material separating portion 8. . In this case, the radius of curvature of the present invention is equal to the radius a of the driven roller 15. The radius of curvature is any point P, P'on the curve.
Is defined as the radius of the largest circle among the circles passing through the two points.

FIG. 4 shows an example in which an image forming apparatus for carrying out the image forming method of the present invention is provided with a drum photosensitive member and a separating roller. Image light is applied to the photoconductor 1 charged by the belt electrode 20 to form a latent image, the developing device 17 forms an image, and the transfer material 4 and the photoconductor 1 are brought into close contact with each other. The transfer material is transferred, and the transfer material is separated from the photoconductor by the separation roller 22 installed in the transfer material separating section 8 and sent to the fixing device 21 by the transport mechanism 5. The separation roller 22 is controlled by the voltage application unit 23 and the control unit 24 so that the separation can be smoothly performed. The toner remaining on the photoconductor is removed by the cleaning device 19. The static elimination lamp 16 is
Excludes electrostatic charges on the photoconductor.

Generally, in the image forming method using an electrostatic latent image, the cleaned toner is discarded after being collected. However, considering the influence on the environment, it is desirable that no waste toner is generated. Therefore, in order to recycle the waste toner, after transferring the toner developed on the latent image bearing member onto the transfer paper, the toner remaining on the photosensitive member is recovered by the cleaning method and returned to the developing device or the toner hopper. In recent years, an image forming method having a mechanism for reusing (recycling process) has been increasingly adopted.

The image forming apparatus for carrying out the image forming method of the present invention may be equipped with a so-called toner recycling system for reusing the cleaned toner. FIG. 5 is an explanatory diagram showing a specific configuration of an example of the toner recycling system. Image light is applied to the photoconductor 1 charged by the belt electrode 20 to form a latent image, the developing device 17 forms an image, and the transfer material 4 and the photoconductor 1 are brought into close contact with each other. The material is separated, and the transfer material is sent to the fixing device 21 by the transport mechanism 5. The toner remaining on the photoconductor is removed by the cleaning device 19.
The charge eliminating lamp 16 removes electrostatic charges on the photoconductor. The residual toner removed by the cleaning device 19 is collected by the recycling mechanism 26, sent to the developing device 17, and used again for image formation. In this case, the separation performance can be improved by adding the separation aid to the initial developer without adding the separation aid to the replenishment toner. Is more preferred.

As a means for interposing the separation aid between the photoconductor and the transfer material in the separation step, 0.05 to 5.0 parts of the separation aid as described above per 100 parts of the colored particles is used. The method of addition is good. If the addition amount is 0.05 parts or less, the effect of the present invention cannot be exhibited, and even if 5 parts or more is added, separation performance tends to saturate, and further improvement in performance cannot be expected. May cause pollution. In this case, when the saturation magnetization is larger than 10 emu / g, the amount of the separation aid adhering to the photoconductor is not sufficient because the magnetic binding force to the developing sleeve is large, which causes a problem in the separation performance. Further, it is preferably 5 emu / g or less.

As the means for interposing the separation aid between the photoconductor and the transfer material in the separation step, in addition to the method of incorporating the separation aid in the above-mentioned developer, the development for exclusive use of the separation aid is carried out. The object of the present invention can also be achieved by a method of separately providing a device or a method of previously attaching a separation aid to paper.

The saturation magnetization referred to in this patent is 1 KO for a sample.
The value when a magnetic field of e is applied, the vibrating sample magnetometer V
It can be measured using SM-3S-15 (manufactured by Toei Industry Co., Ltd.) or the like.

The effects of the present invention are particularly effectively exhibited in the electrostatic separation system in which an electric force is applied between the photoconductor and the separation means during the separation step. As a method of applying an electric force, a method of applying a direct current bias through a roller (Fig. 4), a method of applying an electric charge from the back of the transfer paper by corona discharge (Fig. 1), both corona discharge and direct current bias And the like.

The effects of the present invention are particularly effective in a corona transfer system in which electric charges are applied from the back surface of the transfer paper by corona discharge during transfer.

The effects of the present invention are effective in the separation process in which the surface roughness Rz of the photoconductor is 0.2 μm or less. This is because when the surface roughness of the photoconductor is small, the electrostatic adhesion to the paper becomes strong and the separation performance is severe.

The surface roughness Rz of the photoconductor is, for example, the surface roughness defined in Japanese Industrial Standard JIS B0601-1982, which is a ten-point average roughness at a reference length of 2.5 mm.
The measurement is performed with a surface roughness meter made by Taylor Hopsonne or a universal surface tester made by Kosaka Laboratory.

As the separation aid of the present invention, various inorganic particles,
Various resin particles and further composite particles in which inorganic particles are present on the surface of the resin particles are used.

Particularly, in the image forming process using an amorphous silicon photoconductor as the latent image carrier, the composite particles or the Mohs hardness is 3 to 9.5 from the viewpoint of appropriately polishing the photoconductor and not damaging it. Inorganic particles having a shape factor in the range of 1.05 to 5.00 are preferable. Further, as the separation aid used in the image forming process using the organic photoconductor as the latent image carrier, composite particles, resin particles having a shape factor of 1.00 to 2.00, and inorganic particles are suitable. .

The shape factor in the present invention means a shape factor = (L when the projected area of the separation aid is S and the diameter of the separation aid is L in a photograph taken with a scanning electron microscope. ² × π / 4) / S ² , and a value closer to 1 indicates a more spherical shape. Here, the diameter L of the separation aid means the diameter of the smallest circle among the circles inscribed with the separation aid.

As the inorganic particles constituting the separation aid, various inorganic oxides, nitrides, borides, etc. are preferably used. For example, silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide,
Examples thereof include chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride and boron nitride. Furthermore, the inorganic particles may be subjected to a hydrophobic treatment. When performing the hydrophobic treatment, it is preferable to perform the hydrophobic treatment with a so-called coupling agent such as various titanium coupling agents and silane coupling agents, and further higher fatty acids such as aluminum stearate, zinc stearate and calcium stearate. Hydrophobic treatment with a metal salt is also preferably used.

On the other hand, as the resin particles constituting the separation aid, vinyl-based organic particles are generally preferable, and the reason is that they can be easily produced by a production method such as an emulsion polymerization method or a suspension polymerization method. Because it is possible. Specifically, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methylstyrene,
Chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, p- Styrene or styrene derivative such as n-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-methacrylate
-Butyl, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate
Octyl, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, methacrylic acid ester derivatives such as dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic Acid n-butyl, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate,
Acrylic acid ester derivatives such as dimethylaminoethyl acrylate and diethylaminoethyl acrylate can be mentioned as materials for forming the resin particles. These can be used alone or in combination.

Further, as materials for constituting the other vinyl resin particles, olefins such as ethylene, propylene and isobutylene, halogen vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride,
Vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl carbazole; N-vinyl compounds such as vinylindole and N-vinylpyrrolidone, vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylonitrile, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, methacrylamide, N And acrylic acid or methacrylic acid derivatives such as -butylmethacrylamide and N-octadecylacrylamide. These vinyl monomers can also be used alone or in combination.

Further, it is necessary that the separation aid is stable even when the developer is used for a long period of time.
For this purpose, it is preferable to crosslink the resin particles themselves with various crosslinking agents and use the resin particles having a high hardness.

Examples of the cross-linking agent include divinylbenzene,
Examples include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate. The amount of the crosslinking agent used is appropriately adjusted depending on the required degree of crosslinking, and is preferably used in an amount of 0.1 to 5% by weight based on the vinyl monomer. If the amount of the cross-linking agent is excessive, the hardness increases, but the brittleness becomes brittle, and on the contrary, there is a problem that the durability decreases. If the amount of the cross-linking agent is too small, the effect of the cross-linking agent cannot be exerted.

The resin particles can be produced by an emulsion polymerization method or a suspension polymerization method. Emulsion polymerization is a method of adding the above monomer to water containing a surfactant and emulsifying it, and then polymerizing it, and as the surfactant, sodium dodecylbenzene sulfonate, polyvinyl alcohol, ethylene oxide adduct, and higher Any substance used as a surfactant such as alcohol sodium sulfate can be used and is not particularly limited.
Furthermore, the use of a reactive emulsifier, a hydrophilic monomer, for example, polymerization with a persulfate initiator such as vinyl acetate or methyl acrylate, a method of copolymerizing a water-soluble monomer, a water-soluble resin or A so-called non-emulsion polymerization method such as a method using an oligomer, a method using a decomposable emulsifier, a method using a cross-linking emulsifier is also suitable. Examples of reactive emulsifiers include sulfonates of acrylic acid amides and salts of maleic acid derivatives. The emulsion-free polymerization method has no influence of the residual emulsifier and is suitable when organic fine particles are used alone.

The polymerization initiator necessary for synthesizing the resin particles includes peroxides such as benzoyl peroxide and lauryl peroxide, and azo polymerization initiation such as azobisisobutyronitrile and azobisisovaleronitrile. Agent. The addition amount of these is preferably 0.1 to 2% by weight with respect to the monomer. If the amount is less than this amount, the polymerization reaction is insufficient and the problem of residual monomer itself occurs. Further, if the amount is too large, the decomposition product of the polymerization initiator remains and affects the charging property, and further, the polymerization reaction is too fast, which causes a problem that the molecular weight becomes small. Furthermore, in the emulsion polymerization method or the like, potassium persulfate, sodium thiosulfate or the like can be used as a polymerization initiator.

Further, particles obtained by dissolving the polymers obtained by the above-mentioned various polymerizations, solution polymerizations, bulk polymerizations, etc. in a solvent and granulating by a spray dry method are preferable, from the viewpoint of particle size controllability and shape controllability. Emulsion polymerization is more preferred.

Further, when used as resin particles, if Tg is low, heat generated by energy such as stirring in the developing machine or heat generated in the machine causes a problem of fusion with the toner or carrier. Occur. Therefore, T
The g is preferably 50 ° C. or higher. This control of Tg can be obtained by controlling the compositions of various monomers constituting the above-mentioned resin particles.

Composite particles can be used as the separation aid of the present invention, and the composite particles can be prepared by the following method.

(1) Method of polymerizing resin monomer constituting resin particles in the presence of inorganic particles (2) Method of polymerizing resin monomer constituting resin particles and then associating the inorganic particles with the resin particles (3) A method of electrostatically attaching inorganic particles to the surface of resin particles. In this case, the particle size of the inorganic particles / the particle size of the resin particles = 1 /
(4) After the treatment of (3) above, a method of further applying a mechanical impact force to fix the resin particles to the surface thereof (5) Mixing the resin and the inorganic particles, kneading them, and then pulverizing And a method for obtaining composite particles by further classifying as necessary. As the resin particles used in the above (1) to (4), the same materials as the resin particles used without being combined with the inorganic particles are used. be able to.

Examples of the binder resin of the composite particles produced by the kneading and pulverizing method as described in (5) above include polyester resin, styrene-alkyl acrylate resin, styrene-alkyl methacrylate resin, styrene- Butadiene resin, styrene-acrylonitrile resin, styrene-acryl-polyester resin, styrene-acryl-crystalline polyester graft resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl chloride,
Examples thereof include polyamide, polyvinyl butyral, rosin, modified rosin, phenol resin, xylene resin and the like.

The average primary particle size of the inorganic particles present on the surface of the composite particles constituting the separation aid is the number average particle measured by image analysis by observing with a scanning electron microscope or a transmission electron microscope. Refers to the diameter.

As the method of adding the separation aid according to the present invention to the developer, in addition to the method of mixing with the toner, 2
In the case of a component developer, if it is used in an image forming method equipped with a toner recycling mechanism that uses the toner collected in the cleaning step again in the developing step, it is mixed with a carrier. It is mixed with a mixture of toner and carrier. A method of mixing the toner and the carrier at the same time may be mentioned, but the method of mixing with the toner is preferable because it helps the dispersion of the separation aid, and when the fluidizing agent is added to the colored particles to form the toner. The method of adding the fluidizing agent and then adding the separation aid is preferable in that the adhesion of the fluidizing agent to the toner is not hindered.

In the present invention, the toner concentration is 2 to 15 parts by weight, more preferably 4 to 5 parts by weight, based on 100 as a whole developer.
12 parts by weight is preferred.

The toner particle size is preferably 5 to 15 μm. From the viewpoint of image quality, 12 μm or less is preferable.

As the raw material for the toner used in the present invention, all known materials can be used. First, as the binder resin, for example, polyester resin, styrene-alkyl acrylate resin, styrene-alkyl methacrylate resin, Styrene-butadiene resin, styrene-acrylonitrile resin, styrene-acryl-polyester resin, styrene-acryl-crystalline polyester graft resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl chloride, polyamide, polyvinyl butyral, rosin, modified rosin , Phenol resin, xylene resin and the like.

As the colorant, for example, carbon black,
Chrome yellow, Dupont oil red, quinoline yellow, phthalocyanine blue, and magnetic substances. Ferromagnetic materials such as ferrite, magnetite, and other metals or alloys exhibiting ferromagnetism such as magnetite, compounds containing these elements, or ferromagnetic materials that do not contain ferromagnetic elements, but are ferromagnetic Showing an alloy such as manganese-copper-aluminum,
Examples thereof include alloys called Heusler alloys containing manganese such as manganese-copper-tin and copper.

As the charge control agent, a nigrosine dye, 4
A secondary ammonium salt compound, an alkylpyridinium compound, a triphenylmethane compound, and an organic salt or complex containing a divalent or higher metal can be used.

Examples of the releasing agent include low molecular weight polyethylene having a number average molecular weight (the number average molecular weight indicates a polystyrene molecular weight conversion value in high temperature GPC) of 1500 to 5000, low molecular weight polypropylene and low molecular weight polyethylene.
Polyolefin wax such as polypropylene copolymer,
For example, high-melting paraffin wax such as microwax and Fischer-Tropsch wax, for example, fatty acid lower alcohol ester, fatty acid higher alcohol ester,
Ester wax such as fatty acid polyhydric alcohol ester, amide wax and the like can be used.

The above-mentioned raw materials are appropriately mixed, and colored particles are obtained through the steps of mixing, melting, kneading, cooling, pulverizing and classifying. Alternatively, the colored particles can be obtained by a method of dissolving and dispersing the raw materials in a solvent and polymerizing the raw materials.

Inorganic fine particles and, if necessary, other substances are mixed as external additives. Examples of the inorganic fine particles include silica, alumina, titania, barium titanate, magnesium titanate, calcium titanate,
Examples thereof include strontium titanate, zinc oxide, cerium oxide, antimony trioxide, zirconium oxide, silicon carbide and silicon nitride. These may be hydrophobized before use, and particularly hydrophobized silica is preferable.
Further, in recent years, negatively-charged organic photoconductors are becoming the mainstream as the photoconductor, and toners having positive chargeability are required. Therefore, the chargeability of the hydrophobic silica fine particles is also required to be positively chargeable. For example, amino-modified silane coupling agents, amino-modified silicone oils, polysiloxane ammonium salts, organopolysiloxanes and amine-modified amines such as 3-aminopropyltriethoxysilane. Hydrophobic silica surface-treated with a silicone compound can be preferably used. Other external additives include zinc stearate, lubricants such as polyvinylidene fluoride, and fixing aids such as low molecular weight polypropylene.

The amount of the inorganic fine particles used is 0.
The range of 01 to 5 parts by weight is preferable, and the range of 0.05 to 2 parts by weight is particularly preferable.

[0078]

【Example】

Example 1 <Separation aid> Separation aids 1 to 14 as shown in Table 1 were prepared as separation aids.

[0079]

[Table 1]

<Developer Preparation Example 1> Copolymer of styrene / n-butyl acrylate / methyl methacrylate = 87/8/5 (weight ratio) 100 parts by weight Carbon black 12 parts by weight Polypropylene (number average molecular weight 4000) 4 Parts by weight Charge control agent T-77 (manufactured by Hodogaya Chemical Co., Ltd.) 1 part by weight The above components were mixed, melted, kneaded, pulverized and classified to obtain colored particles having an average particle size of 10.3 μm.

Further, with respect to 100 parts by weight of the colored particles, an average particle diameter of 12 n which has been hydrophobized with hexamethyldisilazane
Average particle size 2 after hydrophobizing 1.0 parts by weight of silica of m
1.0 parts by weight of 0 nm titanium oxide was added. Further, 2.0 parts by weight of separation aid 1 (13 μm) was added to prepare a mixture 1 of toner and separation aid.

6 parts by weight of this mixture 1 and 94 parts by weight of a carrier 1 composed of ferrite particles coated with a methyl silicone resin were mixed to obtain a developer 1.

<Developer Preparation Examples 2 to 7> In the developer preparation example 1, instead of 2 parts by weight of the separation aid 1, the separation aid 2, the separation aid 3, the separation aid 4, and the separation aid 5 are respectively used. , 2 to 7 parts by weight of the separation aid 6 and 7 were used in the same manner as described above, and the mixture 2 to 7 of the toner and the separation aid, and the developer 2 were used in the same manner.
~ 7 were produced.

<Developer Preparation Example A> Developer A was prepared in the same manner as in Developer Preparation Example 1, except that the separation aid 1 was not contained.

<Developer Preparation Example 8> Copolymer of styrene / n-butyl acrylate / methyl methacrylate = 65/23/12 (weight ratio) 100 parts by weight Carbon black 12 parts by weight Polypropylene (number average molecular weight 4000) 4 parts by weight Parts Charge control agent TP-415 (manufactured by Hodogaya Chemical Co., Ltd.) 1 part by weight The above components were mixed, melted, kneaded, pulverized and classified to obtain colored particles having an average particle diameter of 8.0 μm.

Further, to 100 parts by weight of the colored particles, 1.0 part by weight of silica having an average particle diameter of 12 nm which was first subjected to a hydrophobic treatment with dimethyldichlorosilane and then with an ammonium functional polysiloxane was subjected to a hydrophobic treatment. Average particle size 20
nm titanium oxide 0.7 parts by weight was added. Further, 2.0 parts by weight of the separation aid 8 was added to prepare a mixture 8 of the toner and the separation aid.

5 parts by weight of this mixture 8 and 95 parts by weight of the carrier 2 composed of magnetite particles coated with a methyl silicone resin were mixed to obtain a developer 8.

<Developer Preparation Examples 9 to 15> Developer Preparation Example 8
In place of 2 parts by weight of the separation aid 8, 2 parts of the separation aid 6, the separation aid 7, the separation aid 9, the separation aid 3, the separation aid 4, the separation aid 11, and the separation aid 12 are used. A mixture of toner and separation aid 9 was prepared in the same manner except that the parts by weight were used.
.About.15, and developers 9 to 15 were prepared.

<Developer Preparation Example B> Developer B was prepared in the same manner as in Developer Preparation Example 8 except that the separation aid was not contained.

<Comparative Developer Preparation Examples 16 to 18> In Developer Preparation Example 8, 2 parts by weight of the separation aid 8 was used instead of 2 parts by weight of the separation aid 12, the separation aid 13, and the separation aid 14, respectively. Mixtures 16 to 18 of comparative toner and separation aid and further developers 16 to 18 for comparison were prepared in exactly the same manner except that the parts by weight were used.

Table 2 shows the types of the obtained developing agents and the separation aids used in the developing agents.

[0092]

[Table 2]

<Sample 1> Two parts of developer 1 and developer A are used.
Under 0 ° C 50% (relative humidity) environment, the radius of curvature is 3
Using a prototype 1 (FIG. 1 type) of an electrophotographic copying machine, which was created so that a drum-shaped photoreceptor having a positively charged amorphous silicon photosensitive layer can be normally developed at 0 mm, the moving speed of the photoreceptor is 270 mm / sec. The separation performance was evaluated under these conditions. The surface roughness Rz of the used photoconductor is 0.07 μm.

The transfer current was fixed at +120 μA, the separation AC current was fixed at 200 μA, 5 blank sheets were continuously copied while changing the separation DC current in steps of 5 μA, and the degree of winding of the transfer paper around the photoreceptor was visually determined. did.

As a criterion for judgment, when passing horizontally without contacting the separating claw unit, the case where the separating claw unit contacts the separating claw unit but does not hit the tip of the separating claw is regarded as acceptable, and the separation claw can be separated only at the tip. Or, a paper jam was rejected. The absolute value of the lowest DC current that passes the acceptance level is evaluated as the separation limit current (μA) and shown in Table 3.

The basis weight of the paper used for the separation test is 4
The size of the paper was 5 g / m ² , the size was A3, the grain of the paper was perpendicular to the traveling direction of the paper, and the curl direction of the paper was set so that the curl direction was on the photoconductor side (easy to wind around the photoconductor). .

Instead of the photoconductor, the transfer current and the separation current are
A grounded aluminum tube was attached and the current flowing through the aluminum tube was measured. Table 3 shows the evaluation results.

When the developer 1 containing the separation aid of the present invention is used, the current can be separated at a lower current than when the developer A containing no separation aid is used.

<Samples 2 to 5> Developers 1 to 4 and developer A were used in a prototype electrophotographic copying machine 1 to move the photosensitive member as shown in Table 3, the transfer current, the transfer current, and the separation AC. The evaluation was performed in exactly the same manner as in Sample 1 except that the current condition was used. Table 3 shows the evaluation results.

<Samples 6 to 8> Developers 5 to 7 and Developer A were drum-shaped at a temperature of 20 ° C. and 50% (relative humidity) with a radius of curvature of 54 mm and a positively charged amorphous silicon photosensitive layer. Using a prototype 2 (FIG. 1 type) of an electrophotographic copying machine created so that the photoreceptor can be normally developed, under the conditions of the photoreceptor moving speed, transfer current and separation AC current as shown in Table 3, Five blank sheets were continuously copied while changing the separation DC current by 5 μA each, and the degree of wrapping of the transfer sheet around the photoreceptor was visually determined. The surface roughness Rz of the photoconductor used was 0.06 μm. Other evaluation methods are the same as those of the sample 1. Table 3 shows the evaluation results.

<Sample 9> Developer 8 and developer B are 2
Under an environment of 0 ° C and 50% (relative humidity), the radius of curvature is 5
Using a prototype 3 (FIG. 1 type) of an electrophotographic copying machine, which is prepared so that it can be normally developed with a drum-shaped photoreceptor having a negatively charged organic photosensitive layer, the movement of the photoreceptor as shown in Table 3 is performed. Under the conditions of speed, transfer current, and separation AC current, change the separation DC current by 5 μA each and make 5 blank copies.
The sheets were continuously printed, and the degree of winding of the transfer paper around the photoconductor was visually determined. The surface roughness Rz of the used photoconductor is 0.
It was 03 μm. Other evaluation methods are the same as those of the sample 1. Table 3 shows the evaluation results.

<Samples 10 to 13> The developers 9 to 11 and the developer B are shown in Table 3 by using the prototype 3 of the electrophotographic copying machine.
The separation performance was evaluated in exactly the same manner as in Sample 9 except that the conditions of the moving speed of the photosensitive member, the transfer current, and the separation AC current were set as shown in FIG. Table 3 shows the evaluation results.

<Samples 14 to 16> Developer 9, Developer 1
2, developer 13, and developer B were prepared so that they can be normally developed in a drum-shaped photoreceptor having a negatively charged organic photosensitive layer with a radius of curvature of 90 mm in an environment of 20 ° C. and 50% (relative humidity). Using an electrophotographic copying machine prototype 4 (FIG. 1 type), the separation DC current is 5 μm under the conditions of the moving speed of the photoconductor, the transfer current and the separation AC current as shown in Table 3.
While changing by A, 5 blank pages are continuously copied.
The degree of winding of the transfer paper around the photoconductor was visually determined. The surface roughness Rz of the photoconductor used was 0.05 μm. Other evaluation methods are the same as those of the sample 1. Table 3 shows the evaluation results.

<Samples 17 to 19> Developer 9, developer 1
4, developer 15 and developer B were prepared in a 20 ° C. 50% (relative humidity) environment so that they can be normally developed with a drum-shaped photoreceptor having a radius of curvature of 180 mm and a negatively charged organic photosensitive layer. Using an electrophotographic copying machine prototype 5 (FIG. 1 type), the separation DC current was 5 μm under the conditions of the moving speed of the photoconductor, the transfer current and the separation AC current as shown in Table 3.
While changing by A, 5 blank pages are continuously copied.
The degree of winding of the transfer paper around the photoconductor was visually determined. The surface roughness Rz of the photoconductor used was 0.06 μm. Other evaluation methods are the same as those of the sample 1. Table 3 shows the evaluation results.

<Sample 20> Two parts of developer 9 and developer B are used.
Radius of curvature is 1 under 0 ° C 50% (relative humidity) environment
Using a prototype of an electrophotographic copying machine 6 (Fig. 1 type), which was created so that it can be normally developed with a drum-shaped photoreceptor having a negatively charged organic photosensitive layer, the movement of the photoreceptor as shown in Table 3 Under the conditions of speed, transfer current, and separation AC current, change the separation DC current by 5 μA each and make 5 blank copies.
The sheets were continuously printed, and the degree of winding of the transfer paper around the photoconductor was visually determined. The surface roughness Rz of the used photoconductor is 0.
It was 06 μm. Other evaluation methods are the same as those of the sample 1.

The evaluation results are shown in Table 3, but the effect of the present invention is not obtained because the curvature of the photosensitive member is small.

<Sample 21> Using the prototype 9 of the electrophotographic copying machine, the developer 9 and the developer B were subjected to the conditions of the moving speed of the photoreceptor, the transfer current, and the separation AC current as shown in Table 3. Otherwise, the separation performance was evaluated in the same manner as in Sample 9.

The evaluation results are shown in Table 3, but the effect of the present invention is not obtained because the moving speed of the photoconductor is low.

<Sample 22> The developer 16 and the developer B for comparison were tested for the moving speed of the photoconductor, the transfer current, and the separation AC current as shown in Table 3 by using the prototype 3 of the electrophotographic copying machine. The separation performance was evaluated in the same manner as in Sample 9 except under the conditions.

The evaluation results of the separation performance are shown in Table 3, but the effect of the present invention is not obtained because the particle size of the separation aid is small.

<Sample 23> The developer 17 and the developer B for comparison were tested for the moving speed of the photoconductor, the transfer current and the separation AC current as shown in Table 3 by using the prototype 3 of the electrophotographic copying machine. The separation performance was evaluated in the same manner as in Sample 9 except under the conditions.

The evaluation results of the separation performance are shown in Table 3. Although the separation performance is improved, since the particle size of the separation aid is large,
Transfer failure occurred.

<Sample 24> The developer 18 and the developer B for comparison were tested for the moving speed of the photoconductor, the transfer current and the separation AC current as shown in Table 3 by using the prototype 3 of the electrophotographic copying machine. The separation performance was evaluated in the same manner as in Sample 9 except under the conditions.

The evaluation results of the separation performance are shown in Table 3. Although the separation performance is improved, the lightness of the separation aid is low,
Slightly transferred separation aid appeared on the image.

[0115]

[Table 3]

As is clear from Table 3, when the separation limit currents are compared with and without the separation aid, the samples of the present invention show a significant decrease in the required current value in the presence of the separation aid. It can be seen that the separation performance is improved. On the other hand, the sample 20 having a small radius of curvature, the sample 21 having a slow moving speed, and the sample 22 having a small particle size of the separation aid of the present invention have no effect by the separation aid. In addition, the sample 23 having a large particle size of the separation aid
In Sample 24 in which the brightness of the separation aid is outside the scope of the present invention, the effect of the separation aid is recognized, but the image quality obtained is poor and cannot be put to practical use.

[0117]

According to the present invention, it is possible to provide an image forming method and a developer having improved separation performance.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an electrostatic separation unit by a corona discharge in which a photoconductor is a drum.

FIG. 2 is a diagram showing an image forming apparatus for a belt-shaped photoconductor.

FIG. 3 is a diagram showing a separating portion of a belt-shaped photosensitive member.

FIG. 4 is a diagram illustrating an image forming apparatus in which a photoconductor is a drum and a separation unit is formed by a DC bias via a roller.

FIG. 5 is a diagram showing an image forming apparatus having a toner recycling system.

[Explanation of symbols]

 a radius of curvature 1 photoconductor 2 separation claw 3 separation claw unit 4 transfer material 5 transport mechanism 6 separation electrode 7 transfer electrode 8 transfer material separation section 10 document 11, 11 'flash lamp 12 contact glass 13 belt-shaped photoconductor 14 drive roller 15 , 15 'driven roller 16, 16' static elimination lamp 17 developing device 18 transfer separation charger 19 cleaning device 20 belt electrode 21 fixing device 22 separation roller 23 voltage application means 24 control means 25 transfer separation mechanism 26 recycling mechanism

Claims (8)

[Claims] 1. A developing step of developing an electrostatic latent image on a moving photoreceptor, a transferring step of transferring a toner image visualized by the development onto a transfer material, and a transfer material carrying the toner image. In the image forming method including a separation step of separating the photosensitive member, the moving speed of the surface of the photoconductor is 250 mm / se.
c or more, the radius of curvature of the photoreceptor is 30 to 200 mm, and the particle size is 10 to 50 μm. An image forming method, characterized in that it is a separation step of separating the separation aid by being present between the photoconductor and the transfer material. 2. The image forming method according to claim 1, wherein the separation step is an electrostatic separation step. 3. The image formation according to claim 1, wherein the separation aid is present between the photoconductor and the paper by supplying the photoconductor with the separation aid from a developer containing the separation aid. Method. 4. A particle size of 10 to 50 μm, A developer containing a separation aid and a toner. 5. A developing step of developing an electrostatic latent image on a moving photoconductor, a transferring step of transferring a toner image visualized by the development onto a transfer material, and a transfer material carrying the toner image. In the image forming method including a separation step of separating the photosensitive member, the moving speed of the surface of the photoconductor is 250 mm / se.
c or more, the radius of curvature of the photosensitive member is 30 to 200 mm, and the particle size (μm) is 1.1 of the toner particle size (μm).
0 times or more and 10 times or less, [External 3] An image forming method, characterized in that it is a separation step of separating the separation aid by being present between the photoconductor and the transfer material. 6. The image forming method according to claim 5, wherein the separation step is an electrostatic separation step. 7. The separation aid according to claim 5 is provided between the photoconductor and the paper by supplying the separation aid from a developer containing the separation aid to the photoconductor.
The image forming method as described in the above. 8. The particle size (μm) is 1.10 times or more and 10 times or less the toner particle size (μm), and A developer containing a separation aid and a toner.